Disregard any problems with additional filtering, regulation, and the fact that the transformer's primary isn't connected. This is just a simplified example to show what the problem is.
But for simpler routing it would be nice if I didn't have to to do that. I.e. if I could leave the capacitor AB where it is:
Ideally I would like to select the voltages simply by soldering the diodes (and jumper) into different positions while keeping the copper traces the same.
But the placement of the capacitor AB feels wrong.
What are negative (or possibly positive) consequences of doing it this way?
If I understand right, the effective capacitance between A and C in variant 3 is half of what the capacitor AC would provide in variant 2 (assuming the same capacitance for each idividual capacitor). I assume that makes it less effective at smoothing out ripples?
Please consider these details about my situation when writing your answer (if they are relevant), but a general answer is always appreciated:
This is part of a switching power supply at 132kHz (driven by a TNY268).
The diodes are MUR420.
The capacitors are 470µF electrolytic capacitors and you can safely assume their voltage rating is sufficient.
To the right of what's shown in the schematics above, there will be a 100µH inductor in all non-ground rails, and after those another set of the same capacitors plus 100nF ceramic capacitors.